What are shampoos? Why are they used in washing the hair? What ingredients do they contain? What ingredient in shampoo is good for hair growth? Let us find out.
The shampoo is a hair care product, usually in the form of a viscous liquid used in cleansing the hair and scalp. It helps in removing dandruff, dust, unwanted sebum, and residues of other hair care products in the hair and scalp.
Shampoos are used in washing hair because some of the dirt in hair especially sebum is not water-soluble. They cannot be removed by water alone and therefore needs to be dissolved by surfactants.
Since shampoos contain about 10-20% of surfactants, they are therefore best for the washing of hair.
Surfactants emulsify the oils and dirt, enabling them to be washed off by water. The hair and scalp become free of oily dirt and new sebum is produced afterward. Washing of hair with shampoo helps to maintain good personal hygiene and greatly reduces the chances of scalp odor, itching, or inflammation.
How Do Shampoos Work?
Although your hair may look greasy and dull, it is not necessarily dirty unless you are rolling in the mud. The dullness of the hair is due to the greasy substance produced by the skin called sebum.
The function of the sebum is to coat the outer cuticle of each strand of hair and give it a healthy shine. Over time, however, the sebum becomes dull due to the attraction of dirt, dandruff, dust, pollen, and other particles to it.
The accumulation of this dirt causes the hair to stick together and create a tangled and greasy look on your hair.
Sebum is not dissolvable in water (hydrophobic). Other dirt present in hair such as dead skin, dirt, and pollen can be removed by water, but the sebum cannot be removed by using water alone.
The shampoo contains detergents, similar to those found in dishwashing liquids and laundry powder. They function as surface-active agents or surfactants.
Surfactants reduce the surface tension of water. The surface tension of water is the ability of the surface of the water to act as a thin elastic film when it comes in contact with a gas.
When the surface tension of water is reduced, its ability to bind together and form an elastic film reduces and it is able to bind to oily particles.
The detergents act as a binding agent between the water particles and the oil particles. Detergent has a hydrophobic end that binds to the oily sebum and a hydrophilic end which binds to the water particles.
Therefore, the oil is removed from the hair by the detergents and is washed away by water while carrying the sebum with it.
Ingredients Used in Making Shampoos
This is the primary ingredient in the production of shampoo. It makes up about 80% of the volume of the product. The type of water used in the production of shampoo is de-ionized water.
De-ionized water is simply water that has no charge. This is achieved by passing water over electronically charged resins. The electric charge of the resins attract these ions, and the water is free of them.
They are also a primary ingredient in the production of shampoos. They are also known as surfactants and are the main cleaning agents present in shampoos.
Surfactants are produced from fatty acids, which are organic compounds present in animals and plants. The fatty acids used in the production of detergents are mainly from plant sources such as soybean oil, coconut oil, and palm kernel oil.
These fatty acids are used to produce detergents such as sodium lauryl sulfate and ammonium lauryl sulfate.
Surfactants are surface-active ingredients and are therefore able to affect the surfaces of water and oils. Their oil compatible (hydrophobic) and water-compatible (hydrophilic) ends help in the removal of non-soluble dirt in the scalp in hair.
When shampoo is applied to the hair, the hydrophobic end binds the oily particles in the hair while the hydrophilic end binds to the water.
When this happens, the detergent forms a micelle which has the oil trapped within it. This micelle is then washed away by the water, thus making the hair clean.
These are known as viscosity builders. They make the shampoo thick, viscous, and creamy. They make up about 4% of the product.
They do not contribute to the cleaning power of the shampoo. They are used to satisfy the customer’s desire for a rich product. The viscosity of a shampoo does not determine how effective the product is.
However, some of the agents used in increasing the viscosity of shampoos can also be used in stabilizing the formulation and keeping some insoluble particles suspended evenly in the formulation without settling.
Salts and gums are the main viscosity builder in shampoos. Gums like cellulose, guar gum, and xanthan gum are mainly used since they possess gel-like properties.
Apart from the detergents added in shampoos to act as cleansing surfactants, some other types of detergents are added to improve the foam-forming properties of the shampoo.
They are known as alkanolamides, which are also surfactants which affect the surface tension of water. These surfactants cause the water to draw the surface molecules towards the center. This gives water its round shape while trapping air bubbles in it to form bubbles.
Detergents possess this quality but foam boosters such as cocamide diethanolamine (DEA) can create the size and amount of bubbles formed.
Like detergents, they are also produced from fatty acids of plant origin and possess hydrophobic and hydrophilic ends.
Since shampoos contain surfactants that rid the hair of its healthy oil and dry them up, conditioners are added in shampoos to help soften, smoothen, and detangle hair after cleaning it.
Shampooed hair possesses a static charge. Static electricity is formed two different objects rub against each other. When this happens, electrons are transferred from one object to the other.
When the hair is dry after washing with shampoos, there is no sebum present in the hair cuticles and as the hair move against each other, they exchange electrons and become full of static electricity.
This can make the hair strands to repel each other like magnets. This can be taken care of using moisture, hair oils, or conditioners.
Conditioners are added in shampoos to improve the feel of hair after washing and to reduce the static charges. They constitute about 2% of the formulated product.
Conditioning agents added in shampoo are polymers such as hydroxy-propyl-tri-ammonium chloride, a silicone such as dimethicone and quaternium-80 which is a quaternary agent.
Quaternary agents are also surfactants but have poor cleaning power and great wetting property. They leave a soft and smooth feeling on hair and fabrics.
Comprising of about 0.5%o of the shampoo formulation, preservatives help to prevent the growth of microorganisms in the shampoo.
Shampoos are made with water and thus are prone to support microbial growth. This makes it important for preservatives to be added to the formulation.
The storage of shampoos in the damp environment also increases the chances of mold growth and thus, a broad-spectrum preservative is needed to keep the shampoo free from the growth of potentially harmful microbes.
Some of the preservatives used in shampoos are imidazolidinyl urea, DMDM hydantoin, sodium benzoate, methylisothiazolinone, methylchloroisothiazolinone and 2-bromo-2-nitropropane-1,3-diol.
These are sequestering agents added in shampoos to give it a pearly look and make it look opaque. They comprise about 2% of the product and do not add to the cleaning power of the shampoo.
They are just added to increase the aesthetics of the products. They get rid of the dulling effects of water and make the look opaque and richer.
Other ingredients added are pH-balancing agents such as sodium hydroxide (base) and citric acid (acid).
Fragrance, Color, and Additives
They do not contribute to the function of the product but rather increases the acceptability of the product by the user.
These fragrances and pigments should be approved by the government and FD&C.
Other active ingredients such as essential oils, fruit and plant extracts, vitamins, and proteins all add special qualities to the shampoo.
Additives such as zinc pyrithione possess some antibacterial and antifungal properties that make it useful in getting rid of dandruff from hair.
Some ingredients are added in shampoo to protect hair from the effects of the environment and other hair care products. They protect the hair from the heat from dryers, styling aids, chemicals in swimming pools, salt in beach water, and some harsh styling products. The most common protectant added in shampoo is sunscreen.
Ingredients in Shampoos That Could Cause Hair Loss and Healthier Alternatives
Shampoos contain some ingredients that can cause the thinning and loss of hair. Some of these ingredients are
Isopropyl alcohol or propanol, when used in shampoos, can have drying effects on the hair and scalp. This dryness makes hair brittle, and it breaks easily.
However, alcohols like stearyl alcohol and Cetearyl alcohol do not dry out hair. They actually help the hair to retain moisture.
Sulfates like ammonium lauryl sulfate, Sodium Laureth Sulfate, and Sodium Lauryl Sulfate are strong detergents used in producing shampoos.
They bind with the sebum present on the hair and scalp, dirt, dust, pollen, and other residues and get rid of them when rinsed with water.
This strong cleaning ability of these detergents can strip hair of all its protective oils and make the hair brittle and static.
The use of these detergents over time could cause hair thinning and eventual hair loss. Alternatively, look out for ingredients such as sodium lauryl sulfoacetate (SLSA), sodium cocoyl glutamate, decyl glucoside, and lauryl glucoside.
These alternatives are better since they do not completely strip the hair of its natural sebum.
They are used to prevent the growth of microorganisms on cosmetics and shampoos. They are considered to be harmful because they act like estrogen and cause the symptoms of hormonal imbalance.
They are also believed to cause the growth of cancer cells in the breast. They are seen on the labels of the products as methylparaben, propylparaben, and butylparaben.
A healthier alternative to the use of these parabens is sodium benzoate, ethylhexylglycerin, and phenoxyethanol.
Also known as table salt, it is used in shampoos as a thickener. Salt is hygroscopic in nature. This means that it could absorb moisture from its surroundings.
Salt makes the scalp dry and itchy by absorbing the moisture on it and this can lead to hair loss. Dry and curly hair can become drier and brittle when washed with a shampoo that contains sodium chloride.
Natural alternatives used as a thickener in shampoos are cellulose derivatives such as hydroxyethylcellulose, gelatin, and gums such as guar gum, xanthan gum, and locust bean gum.
They are Triethanolamide, Diethanolamide, Monoethanolamine, Monoisopropylamine. They can become nitrosated to form nitrosamines which are carcinogenic in nature.
They are used as emulsifiers and to bind the ingredients used in making shampoos together. They are used as foaming agents and they act as surfactants.
Triethanolamine is made from two toxic compounds, ethylene oxide, and ammonia, neither of which is suitable for hair care.
Only small doses of TEA are approved by the Food and Drug Administration (FDA) for use in cosmetics. They recommend at most 5% concentration of the ingredient because it can be toxic when used in large doses.
TEA is known to cause itchy eyes, dry hair, itchy skin, watery eyes, and brittle hair on a short-term basis.
Natural alternative emulsifiers to look out for are pectin and gelatin.
Synthetic fragrances can irritate the skin and the scalp which can lead to hair loss. Natural essential oils can be used as a natural fragrance in shampoos. Fragrance-free shampoos are also available. They might not be as fragrant as your regular shampoo, but they will clean your hair as a shampoo should.
Ingredients in Shampoo That Can Cause Hair Growth
If your hair loss is caused by hormone changes, age, or male-pattern baldness, it is best to use shampoos that contain Dihydrotestosterone (DHT) blockers. DHT is responsible for the breaking of hair follicles.
DHT blockers to look for in shampoo is pumpkin seed oil, saw palmetto, red clover, and stinging needle.
Hair Follicle Stimulators
Some shampoo ingredients can stimulate the hair follicles and cause hair to grow rapidly. Some of these ingredients are caffeine, biotin, lemongrass oil, aloe vera, and rosemary.
Inflammation causes scalp irritations which leads to hair thinning and loss. Anti-inflammatory agents present in shampoos can tackle this problem and restore normal growth of hair.
Some of the anti-inflammatory ingredients that can be found in shampoos are red clover, green tea extract, and aloe vera.
Antifungal and Antibacterial Ingredients
These ingredients help to control the microbial activities on the scalp and hair follicles and treats dandruff. They also provide the best environment for the growth of hair.
Some of these ingredients are ketoconazole, tea tree oil, and rosemary.
Shampoos are used to get rid of dirt, oils, and dead cells from the hair. Some of the ingredients contained in shampoos can contribute to hair dryness, brittleness, thinning and eventual breakage.
However, some ingredients are being removed from healthy shampoos nowadays. Some ingredients that can get rid of some factors that cause hair loss are also added.
It is, therefore, a good idea to look out for these ingredients while buying your shampoo and reap the benefits of these wonderful ingredients.